TABLE OF CONTENTS The composite materials treated here are made of:
a thermoplastic matrix or binder
an immiscible reinforcement closely bound to the matrix or the binder: fibres of high aspect ratio (length versus diameter), wires, mats, fabrics, foams, honeycombs, plywood and so on.
Hybrids combine plastics or composites with other materials such as metal, wood, etc.
Plastics filled with talc or other powders are not taken into account in this chapter.
The composite properties depend on:
the matrix
the reinforcement
the adhesion between matrix and reinforcement.
The reinforcement, as its name indicates, bears the stresses. When these reinforcements are not randomly distributed, which is often the case, the properties are anisotropic, being enhanced in the reinforcement direction.
The matrix or binder ensures the cohesion of the composite, and distributes and damps the impacts or stresses to protect the composite from the environment.
The cohesion of the matrix and reinforcements can be damaged, even in the bulk, by moisture or chemical surface attack. The fluids can propagate to some depth by absorption and wicking: consequently it is important that a skin protects the reinforcements from direct contact with the external environment.
Composite processing can obtain nearly all part shapes including: plane or warped surfaces; profiles; hollow parts; bulky parts; sheets, slabs and plates; parts with inserts, etc.
Faced by the diversity of plastic composites and their fast evolution, the information here is deliberately general and treats the most widespread cases only. It will be essential for the designer to work in...
